Using the modified Carson's equation [1]}, the self impedance \(z^{aa}\)  and mutual impedances \(z^{ab}\)  and \(z^{ac}\)  of a multi-phase power line can be computed as follows:
\(z^{aa} &=& r_{ik} + 0.095 + j0.121\times H^a_{ik} \Omega \text{/miles}, \\z^{ab} &=& 0.095 + j0.121\times H^{ab}_{ik} \Omega \text{/miles}, \\z^{ac} &=& 0.095 + j0.121\times H^{ac}_{ik} \Omega \text{/miles},\) 
